In order to improve our diagnostic pathology capabilities, we are systematically evaluating commercially available antibodies directed against human cells/tissues for application in the nonhuman primate species housed at the NERPRC. Antibodies are selected for potential usefulness in diagnostic and/or experimental pathology, and for effectiveness in formalin-fixed, paraffin-embedded tissues. In our study we were able to identify 21 of 21 antigens in 4 macaque species and 17 of 21 in for New World species.